This application claims priority of German Patent Application No. 101 59 230.2, filed Dec. 3, 2001.
This invention relates to a method for manufacturing galvanic elements having a liquid organic electrolyte that contain an electrode-separator assembly that has at least one lithium intercalating electrode in whose polymer matrix insoluble, electrochemically active materials are finely distributed in the polymer involved and galvanic elements manufactured according to the method to be described.
In general, electrodes are initially inserted into battery housings, as so-called xe2x80x9chalf-shellsxe2x80x9d, and then electrolyte is added. However, in cases where extremely flat energy-storage devices having thicknesses of less than 0.5 mm for use on, for example, xe2x80x9csmart cardsxe2x80x9d, are involved, that sort of procedure is no longer applicable, since contamination may readily occur in the vicinity of the seal on their cup and cover plate. This is because, in the case of such thin cells, there are no depressions in their housings that the electrolyte may seep back into, which precludes employment of electrolyte-soaked pastes.
In the case of a 3-Volt primary system employing lithium metal and a MnO2-based cathode, the electrolyte is usually either lithium perchlorate, LiClO4, or lithium trifluoromethane sulfonate, CF3SO3Li, dissolved in propylene carbonate (PC), where a viscosity-reducer, such as dimethoxyethane, is added, if necessary. For example, WO 00/57504 discloses a thin-film cell whose positive electrode is manufactured from a paste-mixture of MnO2, carbon, and electrolyte, where the paste involved is prepared in a frame. In the case of a rechargeable 4-Volt system having a carbon anode and a LiMeO2-cathode (Me=Ni, Co, or Mn), lithium hexafluorophosphate, LiPo4F6, in admixtures composed of ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), diethyl carbonate (DEC), or carbonates derived therefrom, are employed. Employment of polymer electrodes consisting of a film fabricated from a copolymer of polyvinylidene difluoride-hexafluoropropylene and similar admixtures is disclosed in U.S. Pat. No. 5,296,318.
It would therefore be advantageous to provide a method for manufacturing galvanic elements having a liquid organic electrolyte for which, in particular, contamination of housing components with electrolyte is prevented and their housing half-shells may be sealed and protected against leakage.
This invention relates to a method for manufacturing galvanic elements including a liquid organic electrolyte and an electrode-separator assembly that has at least one lithium intercalating electrode with a polymer matrix in which insoluble, electrochemically active materials are finely distributed, wherein the electrolyte contains about 2% to about 15% by weight of a hydrocarbon-oxygen compound that has a central carbon atom to which one oxygen atom is doubly bonded and two oxygen atoms are singly bonded, wherein the singly bonded oxygen is not saturated by other atoms or groups and a hydrocarbon chain having a length of four carbon atoms or less is bonded to each of the singly bonded oxygen atoms and the two chains differ by at least one, but no more than three, CH2-groups, including impregnating the electrode-separator assembly with the electrolyte, cutting to a selected size the resulting electrolyte impregnated electrode-separator assembly, and inserting the assembly into a housing.
This invention also relates to a galvanic element including a liquid organic electrolyte containing about 2% to about 15% by weight of a hydrocarbon-oxygen compound that has a central carbon atom, to which one oxygen atom is doubly bonded and two oxygen atoms are singly bonded, wherein the singly bonded oxygen is not saturated by other atoms or groups and a hydrocarbon chain having a length of four carbon atoms or less is bonded to each of the singly bonded oxygen atoms and the two chains differ by at least one, but no more than three, CH2-groups, an electrode-separator assembly that has at least one lithium intercalating electrode with a polymer matrix in which insoluble, electrochemically active materials are finely distributed, and a housing.